Information About vEthernet Interfaces

Virtual Ethernet (vEthernet or vEth) interfaces are logical interfaces. Each vEthernet interface corresponds to a switch interface that is connected to a virtual port. The interface types are as follows:

•VM (interfaces connected to VM NICs)

•Service console

•vmkernel

vEthernet interfaces are created on the Cisco Nexus 1000V to represent virtual ports in use on the distributed virtual switch.

vEthernet interfaces are mapped to connected ports by MAC address as well as DVPort number. When a server administrator changes the port profile assignment on a vNIC or hypervisor port, the same vEthernet interface is reused. This is a change in Release 4.2(1)SV1(4a). In previous releases, the VSM assigned a new vEthernet interface.

When bringing up a vEthernet interface where a change in the port profile assignment is detected, the VSM automatically purges any manual configuration present on the interface. You can use the following command to prevent purging of the manual configuration:

no svs veth auto-config-purge

Guidelines and Limitations

vEthernet interface configuration has the following guideline and limitation:

•MTU cannot be configured on a vEthernet interface.

Default Settings

The following table lists the default settings for vEthernet interface configuration.

Configuring Global vEthernet Properties

You can use this procedure to enable or disable the following automatic controls for vEthernet interfaces:

•Deleting unused vEthernet interfaces

•Purging of manual vEthernet configurations

•Creating vEthernet interfaces

BEFORE YOU BEGIN

Before beginning this procedure, you must know or do the following:

•You are logged in to the CLI in EXEC mode.

SUMMARY STEPS

1. config t

2. (Optional) [no] svs veth auto-delete

3. (Optional) [no] svs veth auto-config-purge

4. (Optional) [no] svs veth auto-setup

5. show running-config all | grep "svs-veth"

6. copy running-config startup-config

DETAILED STEPS

Command

Purpose

Step 1

config t

Example:

n1000v# config t

n1000v(config)#

Enters the global configuration mode.

Step 2

[no] svs veth auto-delete

Example:

n1000v(config)# svs veth auto-delete

n1000v(config)#

(Optional) Enables the VSM to automatically delete DVPorts no longer used by a vNIC or hypervisor port.

The default setting = enabled

The no form of this command prevents the VSM from deleting unused DVPorts.

Step 3

[no] svs veth auto-config-purge

Example:

n1000v(config)# svs veth auto-config-purge

n1000v(config)#

(Optional) Enables the VSM to remove all manual configuration on a vEthernet interface when the system administrator changes a port profile on the interface.

The default setting = enabled

The no form of this command prevents the manual configuration from being deleted in this situation.

Note Port profiles with ephemeral bindings are purged regardless of this setting.

Step 4

[no] svs veth auto-setup

Example:

n1000v(config)# svs veth auto-setup

n1000v(config)#

(Optional) Enables the VSM to automatically create a vEthernet interface when a new port is activated on a host.

The no form of this command disables the automatic creation of vEthernet interfaces in this situation.

Note You can use no form of the command to temporary block automatic creation of vEthernet interfaces.

Step 5

show running-config all | grep "svs-veth"

Example:

n1000v(config)# show running-config all | grep "svs veth"

svs veth auto-setup

svs veth auto-delete

svs veth auto-config-purge

n1000v(config)#

Example:

n1000v(config)# show running-config all | grep "svs veth"

n1000v(config)#

(Optional) Displays the default global vEthernet settings that are in effect on the VSM for verification. If a setting is disabled, it does not display in the show command output.

Step 6

copy running-config startup-config

Example:

n1000v(config)# copy running-config startup-config

(Optional) Saves the running configuration persistently through reboots and restarts by copying it to the startup configuration.

Configuring a vEthernet Access Interface

You can use this procedure to configure a vEthernet interface for use as an access interface.

BEFORE YOU BEGIN

Before beginning this procedure, you must know or do the following:

•You are logged into the CLI in EXEC mode.

•If you do not add a description to the vEthernet interface, then one of the following descriptions is added at attach time. If you add a description and then remove it using the no description command, then one of the following descriptions is added to the interface: